DTC C1099

BHE060201038W07

DTC

C1099

EPS motor

DETECTION CONDITION

• Abnormality detected in control current from EPS control module to EPS motor.

POSSIBLE CAUSE

• Open or short to ground circuit in wiring harness between EPS control module terminal 1A and battery positive terminal
• Open or short circuit in wiring harness between the following EPS control module terminals and EPS motor terminals:
– EPS control module terminal 4A-EPS motor terminal A (L.H.D.) or B (R.H.D.)
– EPS control module terminal 4B-EPS motor terminal B (L.H.D.) or A (R.H.D.)
• Open circuit in wiring harness between EPS control module terminal 1B and battery negative terminal
• EPS control module malfunction
• EPS motor malfunction
• EPS 60 A fuse malfunction
• Noise filter malfunction
• Poor connection of each connector

Diagnostic procedure

STEP

INSPECTION

ACTION

1

INSPECT FUSE

• Inspect EPS 60 A fuse.
• Is EPS 60 A fuse normal?
Yes
Go to the next step.
No
Replace EPS 60 A fuse, then go to Step 10.
2

INSPECT WHETHER MALFUNCTION IS CAUSED BY POOR CONNECTION OF EPS CONTROL MODULE OR PIN DEFORMATION

• Turn the ignition switch off.
• Inspect connection of the EPS control module and wiring harness.
• Disconnect the EPS control module connector.
• Inspect whether malfunction is caused by bent or poorly connected EPS control module connector pin.
• Are the connector connection, connector pins, and wiring harness normal?
Yes
Go to the next step.
No
Repair or replace the faulty connector wiring harness, then go to Step 6.
3

INSPECT EPS MOTOR POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT

• Disconnect the battery positive terminal.
• Inspect for continuity between EPS control module terminal 1A and battery positive terminal.
• Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for open circuit between the EPS control module and battery, then go to Step 10.
4

INSPECT EPS MOTOR POWER SUPPLY CIRCUIT FOR SHORT TO GROUND

• Measure the voltage between EPS control module terminal 1A and ground.
• Is there continuity?
Yes
Repair or replace the wiring harness for short to ground between the EPS control module and battery, then go to Step 10.
No
Go to the next step.
5

INSPECT EPS MOTOR CIRCUIT FOR OPEN CIRCUIT

• Disconnect the noise filter connector.
• Inspect for continuity between the EPS control module terminals and noise filter terminals.
– EPS control module terminal 4A-noise filter terminal a (L.H.D.) or b (R.H.D.)
– EPS control module terminal 4B-noise filter terminal b (L.H.D.) or a (R.H.D.)
• Is there continuity?
Yes
Go to the next step.
No
Replace the noise filter, then go to Step 10.
6

INSPECT EPS MOTOR CIRCUIT FOR OPEN CIRCUIT

• Disconnect the EPS motor connector.
• Inspect for continuity between the EPS motor terminals and noise filter terminals.
– EPS motor terminal A (L.H.D.) or B (R.H.D.)-noise filter terminal a (L.H.D.) or b (R.H.D.)
– EPS motor terminal B (L.H.D.) or A (R.H.D.)-noise filter terminal b (L.H.D.) or a (R.H.D.)
• Is there continuity?
Yes
Go to next step.
No
Repair or replace the wiring harness for open circuit between the EPS motor and noise filter, then go to Step 10.
7

INSPECT EPS MOTOR CIRCUIT FOR SHORT TO POWER

• Measure the voltage between the EPS motor terminals and ground.
– EPS motor terminal A (L.H.D.) or B (R.H.D.)-ground
– EPS motor terminal B (L.H.D.) or A (R.H.D.)-ground
• Is there any B+?
Yes
Repair or replace the wiring harness for short to power between the EPS motor and noise filter, then go to Step 10.
No
Go to the next step.
8

INSPECT EPS MOTOR CIRCUIT FOR SHORT TO GROUND

• Inspect for continuity between the EPS motor terminals and ground.
– EPS motor terminal A (L.H.D.) or B (R.H.D.)-ground
– EPS motor terminal B (L.H.D.) or A (R.H.D.)-ground
• Is there continuity?
Yes
Repair or replace the wiring harness for short to ground between the EPS motor and noise filter, then go to Step 10.
No
Go to the next step.
9

INSPECT EPS MOTOR GROUND CIRCUIT FOR OPEN CIRCUIT

• Disconnect the battery negative terminal.
• Measure continuity between EPS control module terminal 1B and battery negative terminal.
• Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for open circuit between the EPS control module and battery, then go to the next step.
10

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected connectors.
• Clear the DTC from the memory.
• Turn the ignition switch off.
• Start the engine.
• Is the same DTC present?
Yes
Replace the EPS control module, then go to the next step.
No
Go to the next step.
11

VERIFY AFTER REPAIR PROCEDURE

• Are any other DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC Table.)
No
DTC troubleshooting completed.